Hydrofluorocarbons are of great interest due to their potential to replace ozone depleting CFCs used in a variety of applications, including cleaning solvents and blowing agents. For example, 1,1,2,3,3-pentafluoropropane is a useful blowing agent or cleaning solvent (Eur. 381,986) which has been produced as a minor by-product in the cobalt trifluoride fluorination of tetrahydrofuran (J. Burdon et. al. J. Chem. Soc. (C), 1969, 1739).
The art is currently active in searching for methods to reduce chlorofluorocarbons (CFCs) to hydrofluorocarbons (HFC's), to find suitable replacements for ozone depleting CFCs. Simple alkyl halides may be readily dehalogenated via catalytic reduction in the presence of base under mild conditions. However, such dehalogenations are not suitable for the reduction of perhalogenated compounds.
Some CFCs have been reductively dechlorinated in the vapor phase in the presence of a catalyst. However, the reductive dechlorinations of the prior art suffer from a lack of selectivity and reduction control. Reductive defluorination can accompany reductive dechlorination even at relatively low temperatures. For example, EPA 435,705 (Jul. 3, 1991) discloses that the reduction of CF.sub.3 CFCl.sub.2 over iridium on carbon at 150.degree. C. gave CF.sub.3 CHClF (74%) while reduction over palladium under the same conditions gave 95% CF.sub.3 CH.sub.3.
Consequently, there is a need for a process to prepare 1,1,2,3,3-pentafluoropropane using a method which is both economical, and amenable to large scale manufacture.